<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script type="text/javascript" src="js/angular.js" ></script>
		<style type="text/css">
			.red{
				background-color: red;
			}
			.green{
				background-color: green;
			}
			#box{
				height: 200px;
				width: 200px;
			}
			
		</style>
	</head>
	<body ng-app>
		<select ng-model="sss">
			<option value="red" >红色</option>
			<option  value="green">绿色</option>
		</select>
		<div id="box" ng-class="{red:sss=='red',green:sss=='green'}">
		
			
		</div>
		
	</body>
</html>
